Killing effect and mIFN-.GAMMA. expression of gene-viral therapeutic system CNHK300-mIFN-.GAMMA. on malignant tumor cells in vitro

AIM: To investigate the cytotoxicity and mouse IFN-γ(mIFN-γ) expression of oncolytic adenovirus CNHK300-mIFN-γ(CNHK300-Mγ) containing mIFN-γ gene in malignant tumor cells in vitro.METHODS: Human lung cancer cell line A549,human liver cancer cell line SMMC-7721,human pancreatic cancer cell line PANC-1,and human normal fibroblast line BJ were cultured and treated with CNHK300-Mγ,CNHK300,ONYX-015 or AdEasy-mIFN-γ(AdEasy-Mγ).TCID50 assay was used to evaluate the replication ability of CNHK300-Mγ,CNHK300 and ONYX-015 in carcinoma cell lines and normal cell line,and the cytotoxicity was evaluated by cytopathic effect assay and MTT assay.The mIFN-γ expression in the supernatant was detected by ELISA after CNHK300-Mγ or AdEasy-Mγ infection in carcinoma cell lines and normal cell line.RESULTS: The tumor-specific replication ability and cytotoxicity of CNHK300-Mγ were similar to those of CNHK300.The IC50 was as low as MOI of 0.47 pfu/cell for A549 cells,0.074 pfu/cell for SMMC-7721 cells,0.532 pfu/cell for PANC-1 cells and was as high as MOI of 281.73 pfu/cell for BJ cells.CNHK300-Mγ was a more powerful killer of malignant tumor cells than ONYX-015(P0.01).The tumor cells infected with CNHK300-Mγ efficiently expressed mIFN-γ in vitro and mIFN-γ largely increased as the time prolonged in A549,SMMC-7721 and PANC-1 cells.The mIFN-γ expression in the carcinoma cell lines infected with CNHK300-Mγ was much higher than that in the cells infected with AdEasy-Mγ(P0.01),but was similar to that in the normal cell line(P0.05).CONCLUSION: CNHK300-Mγ selectively replicates and effectively promotes the expression of mIFN-γ in carcinoma cells,and specifically kills the tumor cells.